Completely mastering the faster-than-light engine and achieving true mass production was still a long way off, but the bright future of humanity was already laid out before them.
Over the next few days, Russ was required to study various aspects of the Imperium's knowledge.
As a key general of the future Empire, Russ absolutely couldn't be a mere illiterate brute, so his schedule was packed full of lessons.
Though a barbarian by birth, the Primarch's terrifying intellect allowed Russ to make swift progress in his studies.
In the process, he'd also occasionally teach Axis some Imperial literature.
But when it came to Axis's learning abilities… well, hopeless was about the only way to describe them.
Who expects a Saiyan to care about book learning?
It was a complete joke! Sure, fighting was something they were good at.
Anything else?
In Axis's own words; 'Forget it! We're only good at brawling.'
Compared to Russ, Axis really did feel like the true savage here, and the kind who could turn into a giant ape at that!
A few days later, the Emperor met privately with Russ and Axis in a small chamber. Present were only the Emperor's Custodes; not even Horus was allowed inside.
"You're here, have a seat!" The Emperor was in a very good mood, smiling broadly as he greeted Russ and Axis and motioned for them to sit.
"Father! Looks like you're ready to give me my reward." Russ said with a smile.
"Hahaha! What you've given me is indeed extremely valuable. Now, as the Emperor and Master of Mankind, I'm issuing you both a gag order.
"You didn't offer me any ships with FTL engines, only battle armor, energy weapons, power level scouters, and med-pods. This matter must be kept strictly confidential.
"Once you two leave this room today, you're not allowed to remember any of it." The Emperor spoke solemnly.
He had to ensure secrecy. The FTL engine was a matter of enormous importance to humanity.
If these two weren't a Primarch and his chosen future Custodes commander, he might have even wiped their memories entirely.
"I understand, great Master of Mankind. Yesterday, we saw nothing and know nothing." Axis replied promptly.
Clearly, the Emperor was extremely pleased with the FTL engine. The man couldn't hide the joy on his face at all.
"Little cub is right. We only brought a power level scouter, battle suit, energy gun, and med-pod." Russ was quick to play along.
"Good! So, tell me, what reward do you want? The things you've given me are of immense help to the Imperium, and to the future of humanity itself.
"Russ, today, I'll grant you whatever you ask of me." The Emperor said.
"Then I won't be polite, Father. My only request is that, after Axis completes all the Custodes enhancement procedures, he be allowed to return to my side and accompany me on the Great Crusade. That's all I ask." Leman Russ replied.
As soon as these words left Russ's mouth, several Custodes standing guard nearby immediately glanced over.
What Russ said could be seen as highly disrespectful to the Emperor.
It was also something of an insult to the Custodes themselves.
The Custodes didn't truly belong to the Imperium, they belonged solely to the Emperor, as his most loyal guardians.
Every Custodes' power armor and weapons were personally granted by the Emperor, and even their very first names were given by him.
They only followed the Master of Mankind, and only him. For a Custodes to follow a Primarch would be wholly inappropriate.
After all, it would give people the wrong impression:
Questions would inevitably arise.
'Why do none of the other Primarchs have a Custodes at their side, but you do?'
'Could it be the Emperor intends to groom you as his heir?'
But the Emperor was immortal; he didn't need an heir.
Yet, rumours would inevitably spread.
The Emperor looked at Russ seriously and spoke slowly, "Have you made up your mind, Russ? Your request is for Axis to follow you?"
He couldn't simply let the future commander of the Custodes, his personally chosen candidate, be poached so easily. He'd have to think of a solution.
"Yes, Father. That's my request." Russ met his father's gaze; there was every bit of a determined wolf in his expression.
"I understand! If you truly want to keep your little cub at your side, then I can agree to it.
"I've said before: as long as it does not harm humanity or the Imperium, no matter what you ask of me, I will grant it." The Emperor said.
The Emperor agreed so readily that even the Custodes standing guard were surprised.
They'd expected him to refuse outright.
After all, if he agreed to one, what's going to stop the others?
Other Primarchs could might well make the same request.
Surely the Master of Mankind understood this, what was he really planning?
"Thank you so much, Father! Axis and I are very close. I hope that during the coming Great Crusade, he can be by my side, fighting with me for the Imperium and for you." Russ said.
"No need to thank me. This is something I promised you, and I'm simply honoring my word.
"But there are conditions: I'll allow Axis to accompany you during the Great Crusade, but after it ends, he must return to serve as a Custodes." The Emperor replied.
"Father! So you also value my little cub highly." Russ said.
"Yes! The potential in this child is limitless. I have very high hopes for his future," the Emperor said without reservation.
Even without any enhancements, once Axis comes of age, his fighting power might well rival that of a Primarch.
The Emperor was not about to give up on Axis lightly.
"Hahaha, I agree!" Russ laughed.
By the time the Great Crusade ended, little cub would be grown, ready to leave the pack and live on his own!
"Good! Axis will return to Holy Terra with me to undergo the Custodes surgical enhancements. This process will take at least twenty-five years. Once it's done, I'll see to it he rejoins you." The Emperor said.
Unlike the mass-produced Astartes, the Custodes' gene-forging process was highly specialized and customized.
It had to be performed in the Imperial Palace on Terra.
There, Imperial bio-alchemists, and even the Emperor himself, would design and oversee every aspect of the enhancement process, so it would take at least twenty-five years, if not longer.
"No problem." Russ replied.
"Go say goodbye to your father, child.
"Tomorrow, you'll return to Holy Terra with me," the Emperor said to Axis.